VARIABLE-GEOMETRY BLADE FOR AN EOLIC GENERATOR

摘要

The variable-geometry blade for use in a wind driven mechanism comprises a fixed blade portion and a movable winglet portion connected to said fixed blade portion and moveable with respect to said fixed blade portion along a direction substantially transverse to the axis of said fixed blade portion. A guide means is provided to guide the movement of said movable winglet portion with respect to said fixed blade portion, and an actuator means is provided for moving said movable winglet portion with respect to said fixed blade portion between a retracted position and an extended position. The actuator means controls the extension of the movable winglet portion when there is no wind or when the wind is blowing at low speed, and controls the retraction of the movable winglet portion when the wind is blowing at high speed, whereby the movable winglet portion can be moved in an extended position in order to co-operate with said fixed blade portion for increasing the thrust surface at low wind speed, thus allowing a significant increase of the amount of wind power which can be converted into another form of useful power, and the movable winglet portion can be moved in a retracted position at high wind speed in order to reduce the stress at the root of the fixed blade portion, thus allowing the blade to operate within an extended operating range of wind speed.